Middle-Late Pleistocene giant ice-dammed paleolakes occupied in the Pleistocene Uimon (lake volume 450 km3), Kurai (229 km3), Chuya (838 km3), and Kan-Yabogan basins of Gorny Altai, southern Siberia. The lake volumes were estimated along the contours of wave-cut terraces, and Kurai and Chuya lakes taken together turned out to fit the 1056 km3 size of a temporary paleolake, which formed in the Biya-Barnaul segment of the Ob Valley due to f looding of the Fore-Altai plain by megaf loods. However, no megaf lood events were associated with breakthrough of rockfall-dammed lakes in the Chuya and Katun valleys or small ice-dammed lakes in Gorny Altai. Abrupt discharge of lakes through broken ice, landslide, or moraine dams could cause f loods in the Chuya and Katun valleys about 18-14 ka ago, but their volumes and the effects of erosion, sediment transport, and terrain sculpturing were far inferior to those of the older glacial megaf loods.
